Joints, e.g. metal joints, in vehicles (e.g., automobiles, aircraft, boats, etc.) may be formed through the use of an adhesive. For example, an adhesive may be used to bond a metal panel (e.g., a roof panel) to a support structure or chassis of the vehicle. Further, an adhesive may be used in joining two metal panels of a vehicle closure panel assembly. Vehicle closure panel assemblies typically comprise an assembly of an outer and an inner metal panel whereby a hem structure is formed by folding an edge of an outer panel over an edge of the inner panel. Typically, an adhesive is provided there between to bond the panels together. Further, a sealant typically needs to be applied at the joint of the metal panels to provide for sufficient corrosion protection. For example, U.S. Pat. No. 6,000,118 discloses the use of a flowable sealant bead between the facing surfaces of two panels (e.g., of a door), and a thin film of uncured paint-like resin between a flange on an outer panel and the exposed surface of an inner panel. The paint-like film is cured to a solid impervious condition by a baking operation performed on the completed panel assembly (e.g., a door). U.S. Pat. No. 6,368,008 discloses the use of an adhesive for securing two metal panels together forming a joint. The edge of the joint is further sealed by a metal coating. WO 2009/071269 discloses an expandable epoxy paste adhesive as a sealant for a hem flange. A further hemmed structure is disclosed in U.S. Pat. No. 6,528,176.
Further efforts have been undertaken to develop adhesive compositions whereby two panels, e.g. metal panels, in particular an outer and an inner panel of a vehicle closure panel, could be joined with an adhesive without the need for further material for sealing the joint. Thus it became desirable to develop adhesive systems that provide adequate bonding while also sealing the joint and providing corrosion resistance. A partial solution has been described in e.g. WO 2007/014039, which discloses a thermally expandable and curable epoxy-based precursor of an expanded thermoset film toughened foamed film comprising a mixture of solid and liquid epoxy resins, and claimed to provide both favourable energy absorbing properties and gap filling properties upon curing.